This invention relates to a failure alarm device for an appliance, and more particularly to a device posessing two means for enabling an alarm which alarm indicates a mechanical or electrical failure of the appliance main body, capable of fulfilling the alarm function by one means if the other alarm means should fail to function.
An electronic appliance generally possesses a device to alert attention by notifying the user of the abnormality if its operation is abnormal or the occurrence of an abnormality is possible. This device is used not only in electronic appliances but also in all equipment. For the sake of convenience, only an example of an electronic appliance is described below.
The means generally used to notice an abnormality include the following.
a. Acoustic signal by buzzer or voice.
b. Visual signal by lamp or message display.
c. Action signal to stop the machine operation at the safer side. But these alarm means are not perfect, for example:
1. If the alarm itself becomes abnormal, it may be unable to fulfill its function effectively, for example if the buzzer is broken.
2. The signal to control the generation of an alarm is impaired, and the alarm cannot function; for example, the signal wire to sound the buzzer is broken.
3. The machine power source is cut off, and the entire machine including the alarm is stopped in a dangerous state; for example, the power fuse is blown off.
In the event of these abnormalities, the alarm function is not fulfilled.
In the cae of equipment in which an abnormality leads to danger of a man's life, such as medical appliances (blood transfusion pump, etc.), the failure of an alarm function is a serious matter.